Prong forming and driving mechanism

ABSTRACT

PRONG FORMING AND DRIVING MECHANISM FOR PARTICULAR USE IN A MACHINE FOR FORMING LOOP FASTENERS ON WIREBOUND CONTAINERS, HAVING A LOOP BAR WITH A HOOK LIKE EXTENSION AT ITS LOWER END, A FORMER BAR WITH FOR ENGAGING THE END PORTION OF A BINDING WIRE PROJECTING BEYOND THE HOOK-LIKE EXTENSION AND BENDING IT DOWNWARDLY TO FORM A PRONG WHICH IS SUPPORTED ON ITS INSIDE BY THE HOOK-LIKE EXTENSION AND ON THE OTHER THREE SIDES BY THE WALLS OF A GROOVE IN THE FORMER BAR, AND A DRIVER BAR WHICH DRIVES THE PRONG THROUGH THE FACE MATERIAL OF A BOX BLANK WHILE CAMMING THE HOOK-LIKE EXTENSION PROGRESSIVELY OUT OF THE WAY, WITH LATCHING MEANS FOR AUTOMATICALLY LATCHNG AND UNLATCHING THE FORMER BAR TO THE DRIVER BAR AT APPROPRIATE STAGES OF THE CYCLE, SO THAT THE ENTIRE MECHANISM CAN BE DRIVEN BY A SINGLE VERTICALLY RECIPROCABLE CROSSBAR IN A CONVENTIONAL LOOP FASTENER MACHINE.

NOV. 7, 1972 LE ROY VARGA ETAL 3,702,146

PRONG FORMING AND DRIVING MECHANISM 3 Sheets-Sheet 1 Filed May 17, 1971 I Illlllllll INVENTORS Leroy JVI. Vargas T/wmasl. l oorhees ATTORNE LE ROY M. VARGA ETAL 3,702,146

PRONG FORMING AND DRIVING MECHANISM 3 Sheets-Sheet z Nov. 7, 1972 Filed May 17, 1971 Nov. 7, 1972 LE ROY M. VARGA ET AL 3,702,145

PRONG FORMING AND DRIVING MECHANISM 3 M \\\A\\\\v 8 \12 W/ ///w A m, m 3 WM r PT 0 M; CL r\ x x w m M Y y v 5 m Z a A 3 4 a m M m n m w 5 a 2, A T & r 3 w M, w w a w v a B H i W/WZ/ZM Filed May 17, 1971 United States Patent PRONG FORMING AND DRIVING MECHANISM Leroy M. Varga, Dover, and Thomas L. Voorhees, Morris Plains, N.J., assignors to Rockaway Corporation, Rockaway, NJ.

Filed May 17, 1971, Ser. No. 143,760 Int. Cl. B21f 45/00 US. Cl. 140-93 C 6 Claims ABSTRACT OF THE DISCLOSURE Prong forming and driving mechanism for particular use in a machine for forming loop fasteners on wire bound containers, having a loop bar with a hook-like extension at its lower end, a former bar for engaging the end portion of a binding wire projecting beyond the hook-like extension and bending it downwardly to form a prong which is supported on its inside by the hook-like extension and on the other three sides by the walls of a groove in the former bar, and a driver bar which drives the prong through the face material of a box blank while camrning the hook-like extension progressively out of the way, with latching means for automatically latching and unlatching the former bar to the driver bar at appropriate stages of the cycle, so that the entire mechanism can be driven by a single vertically reciprocable crossbar in a conventional loop fastener machine.

This invention relates to mechanism for forming and driving a prong at the end of a wire, for example to secure the free side of a loop fastener at the end of a binding wire on a wire bound container.

The invention is particularly adapted for use in loop fastener machines of the general type disclosed in US. Pat. No. 1,933,031. Such machines are employed to form loop fasteners on wirebound box and crate blanks of the general type disclosed in US. Pat. No. 1,933,030. These box and crate blanks are customarily formed in stapling machines of the general type disclosed in US. Pat. No. 2,482,370 in which properly assembled face material or slats and reinforcing cleats are conveyed by continuously moving conveyor bands beneath stapling heads which drive staples astride longitudinally extending binding wires, through the face material or slats and into the cleats to form a continuous succession of wirebound blanks each comprising several, usually four, side sections foldably secured together by the binding wires. This continuous succession of container blanks is then fed into a loop fastener machine of the type referred to above. In the loop fastener machine, the binding wires are severed in the interval between adjacent blanks, and the binding wires are bent to form prongs in the resulting end portions of the severed binding wires. The binding wires are again bent to form loops in the binding wires and to place the prongs over the adjacent edge portions of the face material of the blanks. The loops are then secured by driving the prongs through the side material and clinching them over against the undersurface thereof. When the blank is folded around to set up the container, the two loop fasteners at opposite ends of each of the binding wires come into opposition at the closing corner of the container and one of these loops, being somewhat narrower than the other, is inserted through the latter and bent down against the outer surface of the box to secure the container closed.

Heretofore, there has been considerable difficulty in the driving of the prongs through the face material of the blank, particularly where the binding wire was of a relatively light gauge or where the face material of the blank was formed of a relatively hard wood. Under these 3,702,146 Patented Nov. 7, 1972 conditions, there was a tendency for the prong to buckle rather than to penetrate the face material. Or if the prong was not directed perpendicularly to the fact material, it could be laterally deflected and skid across the upper surface of the face material rather than penetrating it. In either event, a cull or reject was produced which could be salvaged only by repairing the prong and driving it by hand, an awkward and time-consuming job which substantially added to the cost of producing wirebound container blanks.

It is therefore an object of the present invention to provide a combined prong forming and driving mechanism which supports the prong on all four sides as it is being driven, thereby preventing buckling or deflection and insuring proper penetration of the prong into and through the face material. Another object is that of providing such a mechanism which is relatively simple and inexpensive in construction but reliable and foolproof in operation, and which is susceptible of use in conventional loop fastener machines of the general type described above with only slight modifications which may be quickly and inexpensively effected.

Briefly, these objectives are achieved by modifying the wire cutting heads of the loop fastener machine so that the binding wires are severed in the interval between adjacent box blanks without the usual simultaneous formation of prongs in the resulting cut wire ends; when the binding wires are then bent to form loops therein, the straight end portions of the wires are swung over the opposed edge portions of the face material of the two box blanks, against the edge of a hook-shaped loop bar in a loop forming and driving mechanism of the present invention, with the wire resting on the horizontal portion of the upper edge of a hook-like extension at the lower end of the loop bar, a short distance from the end of the wire. Then a former bar descends to bend the end portion of the wire downwardly around the loop bar to form a prong which is supported on its inner side by the vertical inner face of the loop bar and on its other three sides by the walls of a vertical groove in the inner face of the former bar. Then a driver bar engages the wire to drive the prong through the face material, as the loop bar is moved in synchronism out of the path of the descending horizontal portion of the wire. All of this is accomplished during a single downward stroke of the same reciprocating cross-bar which formerly was used to actuate the driver bar. Thus the mechanism may be readily mounted on the crossbar in place of a conventional driver head, with no other change in the machine except removal of the prong former bar associated with the conventional wire cutter and loop former mechanism.

The exemplary embodiment of the invention shown in the accompanying drawings is intended as merely illustrative of the principles of the invention and not as exhaustive or limiting of the scope thereof, which is defined only by the claims.

In the drawings:

FIG. 1 is a fragmentary perspective view of a loop fastener machine incorporating an illustrative combination prong forming and driving mechanism embodying features of the invention, with the crossbar which actuates the mechanism shown as it nears the end of its upward stroke.

FIG. 2 is a fragmentary vertical and longitudinal sectional view taken generally along the line 2-2 of FIG. 1.

FIG. 3 is a vertical and transverse sectional view taken on the line 33 of FIG. 2.

FIGS. 4 and 5 are views respectively similar to FIGS. 2 and 3 but showing the mechanism in an intermediate stage of the downward stroke of the crossbar.

FIG. 6 is a fragmentary view of the mechanism shown in FIG. 4 at a subsequent stage in the downward stroke.

FIG. 7 is a view similar to FIG. 6 but showing the mechanism at a still later stage of the downward stroke.

FIG. 8 is a fragmentary bottom view of the mechanism taken on the line 88 of FIG. 2.

When the 'loop forming and driving mechanism of the present invention. is installed, as hereabove described, in a conventional loop forming machine of the type described in said Pat. No. 1,933,031, as fragmentarily illustrated in FIGJl, the continuous succession of container blanks B moves through the machine, supported on a table and driven by means of belts (not shown) which engage the lateral edges of the box blanks. When the succession of blanks reaches the position at which the binding wires W in the interval between adjacent b'lanks is properly positioned beneath the wire-cutting heads, the movement of the blanks is momentarily stopped and the table is lowered to place the blanks at the level at which they are shown in FIG. 1. A center crossbar (not shown) is then lowered to cause the wire cutting dies to sever the binding wires W. Then the spindles S are rotated to bend the wires and form loops therein and swing the cut end portions over the adjacent edges of the face material M of the blanks B, on top of the hook-like extensions of the loop bars of the loop forming and driving mechanisms. The outer crossbars C are then driven downwardly to cause the mechanisms to. form prongs in the wire ends and drive them through the face material M and to cause clinchers (not shown) located beneath the table to clinch the prongs over against the under surface thereof. Then the table is again raised and the belts are again started to move the completed blanks out of the machine.

The illustrative prong forming and driving mechanism shown in FIG. 1 includes a support block 10 which is adjustably clamped on the reciprocable crossbar C for movement in unison therewith and which has in its outer face a vertical groove in which a vertical arm 12 is slidably. supported by retaining plates 14 removably secured to the block 10 by screws 16. The lower end of the vertical arm 12 is fixed to one end of a horizontal arm 18 which supports at its opposite end a housing generally designated 20. The housing .20 is thus vertically movable relative to the support block 10, and is urged downwardly by its own weight, with its downward movement being limited by engagement of a lateral extension 12a at the upper end of the arm 12 with the upper ends 14a of the retaining plates 14, as indicated in broken lines in FIG. 1.

The housing 20 is secured to the horizontal arm 18 by a clamp bar 22 and screws 24, with a plurality of selectably removable shims 26 interposed between the arm 1'8 and the housing 20 to permit adjustment of the position of the housing longitudinally of the machine to such position relative to the end of the binding wire W as will produce the length of prong desired. At the time the spindle S is rotated to bendthe binding wire W to form a loop L therein and swing the free end portion E of the wire over the edge of the face material M, as shown in broken lines in FIG. 1, the crossbar C will have been driven downwardly, lowering the housing 20 in unison with it to the point where furtherdownward movement of the housing 20 has been stopped by engagement of the lower end of housing with the upper surface of the face material M of the container blank Asbest shown in FIGS. 3 and 5, supported on the housing 20 for pivotal movement in a transverse vertical plane is a loop bar 30, which is pivotally supported on a pin 32 extending across the housing 20 and is urged to swing in a counterclockwise direction, as viewed in FIG. 5, by a leaf spring 34, the upper end of which is secured by a screw 35 to a support bar 36 extending across the hous-,

ing 20. The counterclockwise movement of the loop bar is limited by engagement of the inner edge of the loop bar with the inner edge of a driver bar 42 supported in the housing 20 in the same vertical plane occupied by the loop bar 30. The loop bar is thus normally held in the vertical position, in which it is shown in FIG. 5.

The end portion E of the binding wire is swung by the spindle S to the point where it engages the inner edge of the loop bar 30, which is provided at its lower end with a hook-like extension 30a which projects laterally in the direction from which the end B of the binding wire approaches. The upper edge of the outer portion 30b of the hook-like extension 30a is inclined downwardly and out- Ward'ly to cam the moving end E of the binding wire upwardly onto the horizontal upper edge of the inner portion 300 of the hook-like extension, as shown in FIGS. 4 and 5, thus positioning the wire properly for the prong forming and driving operation.

The housing 20 is provided with a vertical slot in which a former bar 40 of generally U.-s'haped cross-section is supported for vertical sliding movement, the former bar being held in the slot by a retainer plate 38 and its vertical movement being limited by engagement of an inward ly projecting flange 38a at the lower edge of the retainer plate with the upper and lower ends of a slot 40a in the outer face of the former bar, as respectively shown in FIGS. 3 and 5.

In the vertical slot between the two legs 40c and 40 of the U-shaped former bar, the driver bar 42 is supported for sliding movement, the driver bar 42 being held in the slot in the former bar 40 by engagement of its outer edge with the housing 20 as shown in FIG. 3, and with the inner edge 30d of the loop bar 30, as show in FIG. 5. The vertical movement of the driver bar 42 relative to the former bar 40 is limited by engagement of a pin 44 ex.- tending through the former bar with the upper and lower ends of a slot 42a in the inner edge of the driver bar, as respectively shown in FIGS. 3 and 5.

The upper end of the driver bar 42 is held against the lower face of the crossbar C by engagement of a slot 42b nearthe upper end of the driver bar with a support rail 46 which is secured to the lower face of a hanger block 48 by screws 50. The upper side of the hanger block 48 is provided with a transverse slot which slidably receives the lower edge portion of the crossbar C to permit trans verse movement of the hanger block along the crossbar C together with the support block 10, the hanger block being clamped to the crossbar and held in the adjusted position by bolts 52 (FIG. 1) which extend through openings in a saddle block 54 astride the upper edge of the crossbar C, and which are threaded into the upper edge of the hanger block 48. Thus the driver bar 42 moves vertically in unison with the crossbar C. However, the horizontally slidable engagement of the slot 42b with the support rail 46 allows the driver bar 50 to move along the support rail as the position of the housing is longitudinally adjusted by addition or removal of shims 26, as above described.

The former bar 40 is vertically movable relative to both the driver bar 42 and the housing 20, but can be latched to either for movement in unison therewith by means of a pair of metal detent rollers 56 (FIGS. 2 and 4) which are movably carried in a slot 40b extending through the outer leg 40c of the former bar. The diameter of each of the two rollers 56 is slightly greater than one-half the thickness of the leg 400 so that the rollers either must project from the outer face of the leg 400 into engagement with a recess 58a in a latching plate 58 secured to the inner wall of the housing 20 by screws 60, as shown in FIG. 2, or must project from the inner face of the leg 400 into engagement with a recess 42c in the driver bar 42, as shown in FIG. 4.

After the end -B of the binding wire has been positioned on the hook-like extension 30a of the loop bar 30, as previously described, and as shown in FIGS. 4 and 5, the crossbar C is driven further downwardly, forcing the driver bar 42 downwardly and, since the former bar 40 is then latched to the driver bar 42 by the detent rollers 56, the former bar 40 is also driven downwardly in unison with it.

With the former bar 40 and the driver bar 42 in these relative positions, the lower ends 40d and 40e of the two legs 40c and 40] of the former bar are both spaced below the lower end 42d of the driver bar 42 a distance slightly exceeding the length of the longest prong to be formed. Thus, as shown in FIG. 6, as the former bar descends, the lower end 40d of the outer leg 40c engages the portion of the binding wire W which projects beyond the hook-like extension 30a on the loop bar 30, and bends it downwardly around the loop bar to form a prong P, which is snugly received within a vertical groove 40g in the inner face of the outer leg 40c of the former bar, while the lower end 402 of the inner leg 40 of the former bar depresses the adjacent horizontal portion of the binding wire to form a knuckle K adjoining the prong. The wire is guided into the groove 40g by a funnel-shaped surface 40h in the lower end 40d of the leg 40c, this surface being best shown in FIG. 8.

As the downward movement of the former bar 40 reaches the point shown in FIG. 6, at which the hole 40b in the former bar comes into alignment with the recess 58a in the latching plate 58, further downward movement of the former bar is impeded by engagement of the upper end of the slot 40a in the former bar with the flange 38a on the retainer plate 38. As the driver bar 42 continues downwardly, a bevelled surface 42c at the upper end of the recess 42c in the driver bar cams the detent rollers 56 out of the recess 42c and over into the recess 58a, as shown in FIG. 6, thus unlatching the former bar 40 from the driver bar 42 and latching it to the housing 20. The further downward movement of the driver bar 42 causes its lower end 42d to engage the knuckle K and drive the prong P through the face material M of the container blank, as shown in FIG. 7. As the prong is thus driven, it is supported on the inside by the outer face of the loop bar 30 and on the other three sides by the walls of the groove 40g in the inner face of the former bar 40, so that the prong can neither buckle nor be deflected, and its proper penetration into and through the face material is assured.

As the prong is driven, the loop bar 30 is cammed in a clockwise direction as shown in FIG. 3, against the resistance of the spring 34, by engagement of a cam surface 42 on the edge of the driver bar 42 with a cooperating surface 30h on the loop bar 30. This moves the hook-like extension 30a on the loop bar 30 out of the path of the descending adjacent horizontal portion of the binding wire. The inclination of the upper surface of the outer portion 30b of the hook-like extension progressively reduces the effective height of the hook-like extension as it moves outwardly, in proportion to the reduction of the height of the exposed portion of the prong 'P, so that the inside of the prong is continually supported substantially along its full exposed length until the prong has been fully driven into the face material.

As is more fully disclosed in the aforementioned Pat. No. 1,933,030, after the prong has been fully driven, and as the driver bar 42 continues downwardly, it forces the container blank and the spring loaded supporting table downwardly a short distance, bringing the projecting end portion of the prong P into engagement with a clincher bar (not shown) and causing the clincher bar to bend the prong over and clinch it against the under surface of the face material M, as shown in broken lines in FIG. 7.

As the crossbar C approaches the end of its downward stroke to its lowest position relative to the then stationary housing 20, the housing is latched to the crossbar for upward movement in unison therewith, by means of a latch 60 (FIG. 1) which is pivotally mounted on a pin 62 projecting from the support block and which is spring urged in a clockwise direction, as viewed in FIG. 1, by a compression spring 64 interposed between the outer end 60a of the latch and a finger 10a extending from the support block 10. The opposite end of the latch 60 is provided with a hook 60b which engages a. head 66a on the upper end of a rod 66 extending upwardly from the horizontal arm 18, and laterally supported for vertical sliding movement by a guide bracket 68 secured to the support block 10. The upper face of the head 66a and the lower face of the hook 60b are provided with cooperating cam surfaces so that as they come into engagement near the end of the downward movement of the crossbar C relative to the housing, the latch 60 is rocked in a counterclockwise direction against the resistance of the spring 64 until it clears the head 66a, whereupon it rocks back in a clockwise direction to latch beneath the head 66a.

Thus, after the prong P has been fully driven and clinched, and as the crossbar C is driven back upwardly, it lifts not only the driver bar 42 but also the housing 20, which in turn lifts the former bar 40 and the loop bar 30, so that the mechanism is immediately disengaged from the container blank and the conveyor belts can be started immediately to commence movement of the completed blank out of the machine and movement of the next pair of attached blanks into the machine.

As the crossbar C nears the upper end of its vertical stroke, the outer end 60a of the latch 60 (FIG. 1) engages a stationary unlatching bar 70 which extends across the top of the machine. This rocks the latch 60 in a counterclockwise direction, as viewed in FIG. 1, against the resistance of the spring 64, unlatching the head 66a of the rod 66 and allowing the housing 20 to drop to the position shown in broken lines in FIG. 1. Since the former bar 40 is still latched to the housing by the detent rollers 56, as shown in FIG. 2, it will move downwardly with the housing to the point where the pin 44 carried by the former bar 40 reaches the lower end of the slot 42a in the driver bar 42. Since the driver bar 42 is fixedly supported by the crossbar C, this stops the downward movement of the former bar 40 with the hole 40b in the former bar in alignment with the recess 42c in the driver bar 42. As the housing 20 continues downwardly relative to the former bar 40, a bevelled surface 58b at the upper end of the recess 58a in the latching plate 58 cams the detent rollers 56 out of the recess 58a and over into the recess 420 in the driver bar 42, thereby unlatching the former bar 40 from the housing 20 and latching it to the driver bar 42. The housing 20 will continue to drop until it reaches the relative position shown in FIG. 5, at which the flange 38a engages the lower end of the slot 40a in the former bar, stopping further vertical movement of the housing.

The return of the parts to their relative positions shown in FIGS. 4 and 5 readies the mechanism for a repetition of the sequence described.

I claim:

1. Prong forming and driving mechanism for a loop fastener machine for making wirebound containers, comprising a support, means for adjustably securing said support to a vertically reciprocable crossbar in said loop fastener machine for movement in unison therewith, a driver bar mounted on said support for movement in unison therewith, a housing mounted on said support for vertical sliding movement relative thereto, a loop bar mounted on said housing for movement in a transverse vertical plane, said loop bar having at its lower end a hook-like projection arranged to project beneath the free end portion of a binding wire extending longitudinally from one side of a loop formed in the portion of said binding wire projecting beyond one end of a container blank supported in said machine, a former bar supported in said housing for vertical sliding movement relative thereto, with the inner face of said former bar generallycoplanar with the plane of movement of the adjacent face of said loop bar, said inner face of said former bar having extending from its lower end in line with the end portion of said binding wire, a vertical groove of sufficient width and depth to receive said binding wire, latching means for latching said former bar to said driver bar for vertical movement in unison, control means for unlatching said latching means when the lower end of said former bar has passed a short distance below the upper edge of said hook-like projection on said loop bar, and cooperating cam means respectively associated with said loop bar and said driver bar, and so arranged that, after said former bar has engaged the portion of said binding wire extending beyond said loop bar and bent it downwardly around said loop bar to form a prong in said vertical groove and said latching means has been actuated to unlatch said driver bartfrom said former bar, and as said driver bar continues downwardly independently of said former bar to engage said binding vwire and drive said prong through the face material of said container blank, said cam means causes said loop bar to move outwardly from beneath said binding wire, with said prong as it is thus driven being supported on the inside by said loop bar and on the other three sides by the walls of the vertical groove in said former bar.

2. The mechanism'as described in claim 1 in which the outer portion of the upper edge of the hook-like projection of said loop bar is inclined outwardly and downwardly so that as said prong is driven by said driver bar, the outward movement of said loop bar results in reducing the effective height of the inner face of said hooklike projection in synchronism with the shortening of the portion of said prong remaining exposed above the face material of said container blank.

3. The mechanism as described in claim 1 in which,

said latching means includes detent means transversely movable within a hole in said former bar into and out of engagement with an aligned recess in said driver bar.

4. The mechanism as described in claim 3 in which said detent means is also movable through the other end of the hole in said former bar into and out of engagement with a vrecess in said housing, and wherein bevelled surfaces are provided at the points of contact between said detent means and the upper ends of said recesses to cam said detent means out of said recesses upon relative downward movement of said recesses whereby during the first portion of the downward movement of said driver bar relative to said housing, said detent means locks said former bar to said driver bar until said hole comes into alignment with the recess in said housing, whereupon said detent means is cammed out of the recess in said driver bar and into the recess in said housing to unlock said former bar from said driver bar and lock it to said housing and, upon downward movement of said housing relative to said driver bar, when said hole again comes into alignment with the recess in said driver bar, said detent means is cammed back out of the recess in said housing and into the recess in said driver bar to unlock said former bar from said housing and to lock it again to said driver bar.

5. The mechanism as described in claim 4 in which said detent means comprises one or more metal rollers.

6. The mechanism as described in claim 4 in which a second latch means is provided for latching said housing to said support for vertical movement in unison therewith when said crossbar approaches the lower end of its vertical stroke, whereby said housing willl move upwardly together with said crossbar, and second control means for unlatching said second latch means as said crossbar approaches the upper end of its vertical stroke, whereby such relative downward movement of said housing relative to said driver bar occurs after said mechanism has cleared said container blank to permit commencement of the movement of said container blank out of said machine.

References Cited UNITED STATES PATENTS 2,093,139 9/1937 Rosenmund 140-93 LOWELL A. LARSON, Primary Examiner US. Cl. X.R. 10085 

